Compressive, Flexural Bond, and Shear Bond Strengths of In Situ New Zealand Unreinforced Clay Brick Masonry Constructed Using Lime Mortar between the 1880s and 1940s

Abstract

The importance of sufficient masonry mortar joint-bond strength when a structure is subjected to in-plane and out-of-plane loads has been emphasized by several researchers. However, masonry unit/mortar bond strength is difficult to predict, and performing mechanical tests on existing masonry buildings to determine masonry flexural bond and shear bond strengths is generally not practical, such that predictive expressions relating the masonry flexural bond and shear bond strengths to other masonry properties are desirable. Although relationships between brick/mortar bond and compressive strength have been investigated previously by researchers located in many different parts of the world, most of these studies were laboratory-based and did not include testing of existing masonry buildings within their scope. The writers aimed to characterize the material properties of New Zealand unreinforced clay brick masonry (URM) buildings that were generally built between 1880 and 1930, with in situ testing and sample extraction performed on six heritage buildings. Masonry compression, bond wrench, and shear bond tests were undertaken. The experimental results indicate that the masonry flexural bond strength and bed-joint cohesion can be satisfactorily related to the mortar compressive strength.